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[CQ-Contest] Understanding the dynamic error free RBN algorithm - The DR

 To: cq-contest@contesting.com [CQ-Contest] Understanding the dynamic error free RBN algorithm - The DR1A case José Nunes CT1BOH Thu, 18 Jul 2013 03:26:43 +0100 mailto:cq-contest@contesting.com>
 ```I received several e-mails regarding the understanding of the dynamic error free RBN. In order to explain this graphically I will use the DR1A case from CQWW CW 2012 on 40 meters. DR1A was the most spotted station on 40 meters. DR1A was also busted many times and those busted spots were sent to the RBN Overall there were 8223 spots coming from the real DR1A on the bands: 8114 DR1A spots 109 bust spots of DR1A with the following occurrences - DR1S (24), NR1A (15), DR1T (14), IR1A (11), DR1I (8), DM1A (8), DR4A(7), MR1A (4), KR1A (4), LR1A (3), DR2A (2), DK1AX ( 2), DR1U (2), DD1A (1), DR1AE (1), XR1A (1), DR1N (1) and HR1A (1) As you can see RBN skimmers are very "creative" when it comes to busting good calls. But bear in mind that Skimmer is more accurate than humans. Humans are even more creative when it comes to busting calls, as can be seen in CQWW rpt log checking reports. CT1BOH dynamic error free RBN algorithm catches this dynamic flawlessly. CT1BOH algorithm output for all these 8223 spots is the following: Good Call 7643 92.9% Good call, New Frequency 468 5.7% DR1A Busts 109 1.3% ?Spots 2 0.0% Busted 1 0.0% Let's put only the good spots in a graph. Click the links below to see. http://www.qsl.net/c/ct1boh//dl/good.png The X axis shows the 48 hours of the contest from minute 1 (00:00 Saturday) until minute 2880 (23:59 sunday). The Y axis shows frequency. The scattered dots in the first three hours is DR1A trying to find a good run frequency. If I zoom only for the first three hours this becomes more clear http://www.qsl.net/c/ct1boh//dl/first3.png Let's go back to the original graph with the good spots during the 48 hours, and add the 109 DR1A Busts that Skimmers generated http://www.qsl.net/c/ct1boh//dl/goodandbusts.png CT1BOH algorithm catches all the busted spots and can filter them out of the network Let's now add to the graph the "Good call, New frequency?" spots. By now you know that these spots are the first and the second spots when a new run frequency is established (these are good spots - I know they were 49 spots out of the 468) and the true bad frequency spots from uncalibrated skimmers (I know they are 419 spots) http://www.qsl.net/c/ct1boh//dl/goodbustgnf.png Let's just go a bit deeper in this graphical analysis. Where are all these bad frequency spots coming from? 93 different skimmer from around the world spotted DR1A or busted DR1A call. But not all of them were uncalibrated. http://www.qsl.net/c/ct1boh//dl/skimmers.png If I remove from the graph the six uncalibratted skimmers (MM1PTT/P, F5MUX, HA6PX, DJ4DI, G4HYG, W2RDX) The graph goes from this http://www.qsl.net/c/ct1boh//dl/goodbustgnf.png into this http://www.qsl.net/c/ct1boh//dl/remove6skimmers.png Amazing isn't it. Just removing six uncalibratted skimmer makes a huge difference. One final graph. If we now look at all the spots from those six skimmers http://www.qsl.net/c/ct1boh//dl/datafrom6skimmers.png we clearly see, that they still produce a lot of good spots. They just have to fix that IQ image N4ZR explained in his post. Until then the dynamic error free RBN algorithm will easily filter them out on the spot. By now, I hope I have explained how effective a dynamic free RBN algorithm works. This algorithm is so effective because the network is so big that the good spots will always outnumber the bad spots. Also I would like to explain the price of running this algorithm The price is the first two good spots in a run until the third comes to validate it is a good call. In the case of DR1A the price is 49 spots that are filtered out so that we can drop 520 bad spots Because the network is so big, this price is negligible, i.e. even if we drop the first two spots of a run, chances are that the third spot will be in the same minute. To answer UA9CDC: Parasitic AM Modulation will be much less spotted that the good signal. The good signal will outnumber them, and since they are +/- 1.5 KHz away they will be dropped as "Good call, New Freq?" spot Second and third harmonic will be spotted as good, just like they are today. These are very, very, insignificant cases in the overall number of spots. The algorithm could be enhanced to try to predict these cases, but I don't advice doing it. I'd rather have a false positive than a false negative. No problem with MM stations. The algorithm runs per band. My code was just for one band for demonstration purposes. I understand VE7CC-1 just implemented his version of the dynamic erro free RBN. Also I understand N1MM and AR cluster is also implemented. Soon, busted spots ans wrong frequency spots will be a thing of the past from this extraordinary tool - Reverse Beacon Network 73 José Nunes CT1BOH -- José Nunes CONTEST CT1BOH - http://www.qsl.net/ct1boh _______________________________________________ CQ-Contest mailing list CQ-Contest@contesting.com http://lists.contesting.com/mailman/listinfo/cq-contest ```
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